The molar ratio of insert DNA to vector DNA used in a ligation is generally about 3:1. Using a vector that is 12 kb and an insert that is 4 kb, how much insert would you use if you used 30 ng of vector?

Therefore, required mass of insert DNA is 30 ng

Explanation:

DNA ligation is the process of joining two DNA fragments together through the action of an enzyme for example DNA ligase. The vector DNA often a plasmid is used to insert a desired DNA sequence into a host cell DNA.

The formula for the calculation of required insert DNA mass is given below:

Required mass insert (ng) = desired insert/vector molar ratio x mass of vector (ng) x ratio of insert to vector lengths

Desired insert/vector molar ratio = 3 : 1

Mass of vector = 30 ng

Ratio of insert vector lengths = 4 : 12 = 1 : 3

Required mass of insert DNA = 3/1 × 30 ng x 1/3 = 30 ng

Therefore, required mass of insert DNA is 30 ng

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